JPH0126902Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a shoe friction lining wear indicator for a shoe-drum type brake, in which the thickness of the friction lining carried by the shoe platform that engages with the rotating drum is less than a predetermined value. It relates to a type in which a sensor mounted on the brake shoe activates an indicating means when the brake shoe becomes small, and more particularly to means for mounting the sensor on the shoe.

The friction linings of shoe drum type brakes do not wear evenly because the pressure of the shoe on the drum is not uniform. The center of maximum pressure is located at the circumferential center of the shoe, rather than at the circumferential ends, and therefore it is most effective to locate the lining wear indicator at the circumferential center.

One example of a conventional shoe-drum type brake lining wear indicator is to machine the lining material to insert a sensor near the center of maximum pressure in the lining (for example,
(see publication). This is costly and the performance is not satisfactory. Another example construction is to permanently fasten the sensor to the shoe or lining. This makes it difficult to replace the sensor,
Alternatively, it is inconvenient to replace worn friction linings.

In another construction, the sensor is secured to an electrically insulating block, which is secured to the circumferential end of the shoe. This is easy to install, but is not located at the center of maximum pressure.

The present invention provides a friction lining having an arcuate web, a platform in which a recess is formed, a first surface attached to the platform and a second surface to be engaged with a rotating drum, and a thickness of the friction lining. a brake shoe comprising a friction lining wear indicating device with a sensor for activating an indicating means when the friction becomes less than a predetermined value; and a shoe drum having mounting means for attaching said sensor to said brake shoe. In the brake shoe assembly for type brakes, the recess is formed by deforming a T-shaped portion adjacent to one side edge of the platform radially away from the friction lining; The portion of the first surface facing the recess retains its original shape, the attachment means comprises an elastic clip, the sensor comprises a loop of wire separate from the elastic clip, and the elastic clip is attached to the T-shape. said elastic clip is disposed in a recess and shaped to cooperate with said platform, and said elastic clip is retained within said recess by its own resiliency to hold said sensor in a position of use adjacent said friction lining. It is characterized by:

Although the shoe recess is preferably formed by shearing a portion of the edge of the platform, it is also possible to form it by methods other than shearing. In either case, the recess is configured to accommodate a particular shape or type of attachment means and/or sensor. The recesses may be similar to those commonly formed on the edges of drum brake shoes for the purpose of locating the shoe on the fixed backplate of the brake.

Embodiments of the present invention will be described in detail below with reference to the drawings.

The lining wear indicator shown in FIGS. 1 and 2 is mounted on the brake shoe. The brake shoe has a circular arc web on platform 4.
A lining 5 of friction material is attached to the outer diameter surface of the platform 4 for carrying and engaging a rotating drum (not shown). Lining 5
is attached to the platform using conventional methods. The lining 5 can be pre-molded and fixed to the platform with adhesive or studs. Alternatively, the lining 5 can also be integrally molded onto the platform 4. A recess 7 is provided in the axial edge of the platform 4. The depression 7 is formed by shearing a local part of the platform 4 and is located in the shoe at or near the center of maximum pressure of the drum. The recess 7 can also be provided at other locations on the shoe 2.

a lining wear indicator is located in the recess 7;
It has a sensor 9 held in position by mounting means 10.

The sensor 9 is a loop of wire 12 housed in an insulating material and attached to the axial edge 13 of the lining 5.
is held in a position adjacent to. When the lining has little wear (as shown in the drawing),
The rotating drum does not touch the wire 12. However, as the lining 5 wears, the drum contacts the wire 12 and an indicating device (not shown)
Activate. The wire 12 and the drum are connected to an electrical circuit (not shown) with an indicating device, preferably a warning light. When the drum and sensor come into contact, the circuit is closed or cut off and a warning light is turned on.

In the embodiment of FIGS. 1-6, the lining wear indicator is located in a recess 7 in which a portion of the platform 4 has been sheared off. Recess 7 is approximately T
It is shaped like a cylindrical shape and houses attachment means 10 which include an elastic clip 44 made of metal. Clip 44 (Figure 6)
is generally W-shaped and has a pair of outer arms 45 and a pair of inner arms 46. The outer arm 45 is curved and provides a retention means for retaining the clip 44 within the T-shaped recess 7.

The sensor 9 is a wire loop 1 covered with an insulating material.
2 and held by clips 44 between pairs of adjacent outer arms 45 and inner arms and adjacent linings 5. Clip 44 also overcomes the problem of holding sensor 9 adjacent lining 5 when edge 13 of the lining is stepped to the edge of the platform. As shown in FIGS. 3 and 4, the clip 44, due to its elastic structure and placement within the T-shaped recess 7, can hold the wire 12 in several different positions. I can do it. A recess 47 is provided in the recess 7 to accommodate the wire 12 when the edge 13 of the lining 5 does not extend to the edge 48 of the platform 4, as shown in FIG. Figure 4 shows
The position of the indicator is shown when the edge 13 of the lining 5 is flush with the edge 48 of the platform 4.
These drawings show extremes in the position of the lining on the platform due to manufacturing tolerances.

In the indicator 1, the wire 12 is placed between a pair of adjacent outer arms 45 and inner arms 46, and the outer arms 45 are deformed (FIG. 5) so that the clip 44 can be inserted into the recess 7. It is assembled by The indicator can be removed by simply removing the clip 44 from the recess 7.

The use of metal clips as attachment means has the advantage over plastic closures of being able to withstand the heat generated during operation.

[Brief explanation of the drawing]

FIG. 1 is a top view of an indicator according to an embodiment of the present invention provided in a recess of a brake shoe, and shows an embodiment of the mounting means. FIG. 2 is an end view of FIG. 1. Figures 3 and 4
The figure shows a state in which the indicator is in a different position relative to the recess of the brake shoe in Figure 1. FIG. 5 is a diagram showing a state in which the indicator of FIG. 1 is assembled. 6th
The figure is a diagram showing a means for attaching the indicator of FIG. 1. 1... Indicator, 4... Platform, 5...
...Lining, 7...Dent, 9...Sensor, 1
0... Attachment means, 44... Elastic clip.

Claims (1)

[Claims for Utility Model Registration] (1) A friction lining having an arcuate web, a platform in which a recess is formed, a first surface attached to the platform, and a second surface to be engaged with a rotating drum. and a friction lining wear indicating device comprising a sensor for activating an indicating means when the thickness of the friction lining becomes less than a predetermined value;
In a brake shoe assembly for a shoe drum type brake having mounting means for mounting the sensor on the brake shoe, the recess 7 is located at one side edge 48 of the platform 4.
The T-shaped portion adjacent to the friction lining 5 is deformed and formed so as to be radially separated from the friction lining 5, and the portion of the friction lining facing the recess on the first surface retains its original shape, and the attachment means 10 consists of an elastic clip 44, said sensor consisting of a loop of wire 12 separate from said elastic clip, said elastic clip 44 being placed in said T-shaped recess 7 and having a shape cooperating with said platform. None, sensor 1 above
2 in the position of use adjacent to the friction lining 5, said elastic clip being held in said recess 7 by its own elasticity. (2) The brake shoe assembly according to claim 1, in which the elastic clip 44 is removably attached to the recess 7. (3) In the brake shoe assembly according to claim 1 or 2 of the utility model registration claim, the elastic clip 44 is W-shaped and has a pair of outer arms 45 and a pair of inner arms 46. Brake show assembly. (4) The brake shoe assembly according to claim 3, wherein the outer arm 45 is curved so as to hold the elastic clip 44 in the recess 7.